Experimental Approach and Conventional Analytical Techniques to the Carbon Nanotube Network Interphase in 3-Phase Polymer Matrix Nano-Composites

The interaction between the CNT network and the surrounding polymer and between BP and the surrounding polymer occurs via interphase with different morphology than the bulk matrix. This interphase’s properties have not been given enough attention in the literature, and the purpose of this study is to investigate the interphase properties experimentally and analytically. Atomic Force Microscopy based Peak Force Quantitative Nanomechanics Mapping (PFQNM) technique with the high lateral resolution was used for the characterization of the interphase in 3-phase polymer matrix nano-composites at the nanoscale. Details of the calibration parameters such as probe stiffness, spring constant, tip radius, tapping force, deformation level, synchronous distance, drive3 amplitude sensitivity (DDS3), and deflection sensitivity were discussed. AFM Multimode 8, scanner type J with a maximum scanning window of 125μm × 125μm, was used. The Derjaguin, Muller, Toropov (DMT) equation was applied to the retract curve to calculate the elastic modulus. BP is heterogeneous at the nanoscale due to nonuniform resin impregnation. The average interphase thickness for the CNT network is 27nm in BP, higher than ∼10nm between epoxy and fiber, confirming stronger interphase. The CNT network size in BP nanocomposite is influenced by the inter-bundle and intra-bundle pores in the BP. The Kolarik, Quali, and Takayanagi models for interphase of the CNT network were investigated.